The present invention relates to a system and a method for determining the displacement of two bodies relative to each other.
A system and a method of the type mentioned at the outset are known, for example, from WO 2010/042039 A1. In the known system, a geometrical pattern attached to a first rotatable body is detected by a detector unit, which is attached to a second rotatable body, in multiple rotational positions of the first body and/or second body. Furthermore, a further geometrical pattern attached to the second rotatable body is also detected by a further detector unit attached to the first rotatable body in these rotational positions. In the technical teaching known from WO 2010/042039 A1, the location of the rotational axis of the first rotatable body relative to the rotational axis of the second rotatable body is then determined on the basis of the shifts of the detected geometrical patterns accompanying the change of the rotational positions, wherein the two units or bodies can in particular be shafts to be aligned flush with one another. Each of the detector units has a camera for detecting the geometrical pattern. For the accurate determination of the location of the rotational axes relative to each other, in the known solution, the patterns are to be imaged as precisely and/or sharply as possible on the sensor surface of the image sensor of the respective camera. For this purpose, the cameras have to be focused as precisely as possible on the geometric pattern. The setting of a desired focus has proven to be complex and susceptible to error in practice, since even minor acceleration and gravitational forces as can occur, for example, during the turning of the detector units, can be accompanied by an undesired displacement of the objective lens, which in turn results in inaccuracies in the determination of the location of the rotational axes relative to one another. Such difficulties with the focusing also result, for example, in the solution known from DE 33 35 336 A1. A method and a device for the static alignment of shafts and for the monitoring of the shaft alignment are known from DE 33 35 336 A1.